U.S. patent application number 15/537037 was filed with the patent office on 2017-12-28 for conveyance system having paralleled drives.
The applicant listed for this patent is Otis Elevator Company. Invention is credited to Ismail Agirman, Jeffrey M. Izard, HanJong Kim.
Application Number | 20170369276 15/537037 |
Document ID | / |
Family ID | 55022725 |
Filed Date | 2017-12-28 |
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United States Patent
Application |
20170369276 |
Kind Code |
A1 |
Agirman; Ismail ; et
al. |
December 28, 2017 |
CONVEYANCE SYSTEM HAVING PARALLELED DRIVES
Abstract
A conveyance system includes a machine having a motor; a source
of AC power; a drive system coupled to the source of AC power, the
drive system to provide multi-phase drive signals to the motor, the
drive system including: a first drive having a first converter and
a first inverter, the first convertor including a first positive DC
bus and a first negative DC bus; a second drive having a second
converter and a second inverter, the second convertor including a
second positive DC bus and a second negative DC bus; wherein the
first positive DC bus and the second DC positive bus are
electrically connected and the first negative DC bus and the second
negative DC bus are electrically connected.
Inventors: |
Agirman; Ismail;
(Southington, CT) ; Izard; Jeffrey M.; (Bolton,
CT) ; Kim; HanJong; (Avon, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Otis Elevator Company |
Farmington |
CT |
US |
|
|
Family ID: |
55022725 |
Appl. No.: |
15/537037 |
Filed: |
December 9, 2015 |
PCT Filed: |
December 9, 2015 |
PCT NO: |
PCT/US2015/064627 |
371 Date: |
June 16, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62093130 |
Dec 17, 2014 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02M 7/487 20130101;
H02M 5/4585 20130101; B66B 1/308 20130101; H02M 2001/0067 20130101;
H02P 4/00 20130101; H02M 7/49 20130101; H02P 27/14 20130101; H02P
25/22 20130101; H02M 1/12 20130101 |
International
Class: |
B66B 1/30 20060101
B66B001/30; H02M 7/487 20070101 H02M007/487; H02M 7/49 20070101
H02M007/49; H02M 5/458 20060101 H02M005/458; H02M 1/12 20060101
H02M001/12 |
Claims
1. A conveyance system comprising: a machine having a motor; a
source of AC power; a drive system coupled to the source of AC
power, the drive system to provide multi-phase drive signals to the
motor, the drive system including: a first drive having a first
converter and a first inverter, the first convertor including a
first positive DC bus and a first negative DC bus; a second drive
having a second converter and a second inverter, the second
convertor including a second positive DC bus and a second negative
DC bus; wherein the first positive DC bus and the second DC
positive bus are electrically connected and the first negative DC
bus and the second negative DC bus are electrically connected.
2. The conveyance system of claim 1, wherein the first converter
includes a two level, three phase converter, the first inverter
includes a two level, three phase inverter, the second converter
includes a two level, three phase converter, and the second
inverter includes a two level, three phase inverter.
3. The conveyance system of claim 1, further comprising: an
inductive interface coupled to the first inverter and the second
inverter, the inductive interface including a plurality of
inductive elements, the inductive interface combining drive signals
from the first inverter and the second inverter for each phase of
the drive signals; wherein the motor receives the drive signals
from the inductive interface.
4. The conveyance system of claim 1, wherein the first converter
includes a three level, three phase converter, the first inverter
includes a three level, three phase inverter, the second converter
includes a three level, three phase converter, and the second
inverter includes a three level, three phase inverter.
5. The conveyance system of claim 4, wherein the first converter
includes a first converter neutral point, the first inverter
includes a first inverter neutral point, the second converter
includes a second converter neutral point, the second inverter
includes a second inverter neutral point, the first converter
neutral point electrically connected to the first inverter neutral
point and the second converter neutral point electrically connected
to the second inverter neutral point, wherein the first converter
neutral point is not electrically connected to the second inverter
neutral point and the first inverter neutral point is not
electrically connected to the second converter neutral point.
6. The conveyance system of claim 4, wherein the first converter
includes a first converter neutral point, the first inverter
includes a first inverter neutral point, the second converter
includes a second converter neutral point, the second inverter
includes a second inverter neutral point, wherein at least one of
(i) the first converter neutral point is electrically connected to
the second inverter neutral point and (ii) the first inverter
neutral point is electrically connected to the second converter
neutral point.
7. The conveyance system of claim 6, further comprising a neutral
point link electrically connecting the first converter neutral
point to the first inverter neutral point.
8. The conveyance system of claim 7, further comprising a second
neutral point link electrically connecting the second converter
neutral point to the second inverter neutral point.
9. The conveyance system of claim 1 wherein the drive system
comprises a first drive controller to provide a first control
signal to the first drive and a second drive controller to provide
a second control signal to the second drive.
10. The conveyance system of claim 9 wherein the first drive
controller communicates a location of a reference point in the
first control signal to the second drive controller, the second
drive controller adjusting a period of the second control signal in
response to the location of the reference point in the first
control signal.
11. The conveyance system of claim 10 wherein the reference point
in the first control signal corresponds to point in a PWM control
signal.
12. The conveyance system of claim 10 the second drive controller
adjusts the period of the second control signal using a phase
locked loop.
13. The conveyance system of claim 1 wherein the first converter is
a three level, three phase converter, the first inverter is a two
level, three phase inverter, the second converter is a three level,
three phase converter, the second inverter is a two level, three
phase inverter and the motor is a six phase motor.
14. The conveyance system of claim 1 further comprising: a second
drive system coupled to the source of AC power, the second drive
system to provide multi-phase drive signals to the motor, the
second drive system including: a further first drive having a
further first converter and a further first inverter, the further
first convertor including a further first positive DC bus and a
further first negative DC bus; a further second drive having a
further second converter and a further second inverter, the further
second convertor including a further second positive DC bus and a
further second negative DC bus; wherein the further first positive
DC bus and the further second DC positive bus are electrically
connected and the further first negative DC bus and the further
second negative DC bus are electrically connected; the motor to
receive the drive signals from the further first drive and the
further second drive.
15. The conveyance system of claim 14 further comprising: a first
inductive interface coupled to the first inverter and the second
inverter, the first inductive interface including a plurality of
inductive elements, the first inductive interface combining drive
signals from the first inverter and the second inverter for each
phase of the drive signals; and a second inductive interface
coupled to the further first inverter and the further second
inverter, the second inductive interface including a plurality of
inductive elements, the second inductive interface combining drive
signals from the further first inverter and the further second
inverter for each phase of the drive signals; wherein the motor
receives drive signals from the first inductive interface and the
second inductive interface.
16. The conveyance system of claim 15 wherein: the first inductive
interface generates three phase drive signals; the second inductive
interface generates three phase drive signals; and the motor has at
least six phases.
17. The conveyance system of claim 14 wherein: the motor is a 6
phase motor, the first drive system providing three phase drive
signals and the second drive system providing an additional three
phase drive signals.
18. The conveyance system of claim 14 wherein: the number of drive
systems comprises N drive systems, the motor being a 3N phase
motor.
19. The conveyance system of claim 1 further comprising: an
elevator car; the machine to control motion of the elevator car.
Description
TECHNICAL FIELD
[0001] The subject matter disclosed herein relates generally to
conveyance systems, and more particularly to a conveyance system
having drives arranged in an electrically parallel manner.
BACKGROUND
[0002] Conveyance systems, such as elevator systems, use machines
to impart force to a car carrying passengers. The machines employed
may need to provide varying power levels depending on the
application. When an elevator requires a large elevator duty or
load, a drive needs be provided to power the elevator machine.
Often, a high power drive may not exist, which results in high
design costs and lengthy development time to manufacture a suitable
drive. Even if a single, large drive exists in the marketplace,
costs associated with a single, large drive may be excessive due to
specialty components, component availability, etc.
BRIEF SUMMARY
[0003] According to an exemplary embodiment, a conveyance system
includes a machine having a motor; a source of AC power; a drive
system coupled to the source of AC power, the drive system to
provide multi-phase drive signals to the motor, the drive system
including: a first drive having a first converter and a first
inverter, the first convertor including a first positive DC bus and
a first negative DC bus; a second drive having a second converter
and a second inverter, the second convertor including a second
positive DC bus and a second negative DC bus; wherein the first
positive DC bus and the second DC positive bus are electrically
connected and the first negative DC bus and the second negative DC
bus are electrically connected.
[0004] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the first converter includes a two level, three phase
converter, the first inverter includes a two level, three phase
inverter, the second converter includes a two level, three phase
converter, and the second inverter includes a two level, three
phase inverter.
[0005] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
an inductive interface coupled to the first inverter and the second
inverter, the inductive interface including a plurality of
inductive elements, the inductive interface combining drive signals
from the first inverter and the second inverter for each phase of
the drive signals; wherein the motor receives the drive signals
from the inductive interface.
[0006] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the first converter includes a three level, three phase
converter, the first inverter includes a three level, three phase
inverter, the second converter includes a three level, three phase
converter, and the second inverter includes a three level, three
phase inverter.
[0007] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the first converter includes a first converter neutral
point, the first inverter includes a first inverter neutral point,
the second converter includes a second converter neutral point, the
second inverter includes a second inverter neutral point, the first
converter neutral point electrically connected to the first
inverter neutral point and the second converter neutral point
electrically connected to the second inverter neutral point,
wherein the first converter neutral point is not electrically
connected to the second inverter neutral point and the first
inverter neutral point is not electrically connected to the second
converter neutral point.
[0008] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the first converter includes a first converter neutral
point, the first inverter includes a first inverter neutral point,
the second converter includes a second converter neutral point, the
second inverter includes a second inverter neutral point, wherein
at least one of (i) the first converter neutral point is
electrically connected to the second inverter neutral point and
(ii) the first inverter neutral point is electrically connected to
the second converter neutral point.
[0009] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include a
neutral point link electrically connecting the first converter
neutral point to the first inverter neutral point.
[0010] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include a
second neutral point link electrically connecting the second
converter neutral point to the second inverter neutral point.
[0011] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the drive system comprises a first drive controller to
provide a first control signal to the first drive and a second
drive controller to provide a second control signal to the second
drive.
[0012] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the first drive controller communicates a location of a
reference point in the first control signal to the second drive
controller, the second drive controller adjusting a period of the
second control signal in response to the location of the reference
point in the first control signal.
[0013] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the reference point in the first control signal corresponds
to point in a PWM control signal.
[0014] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
the second drive controller adjusts the period of the second
control signal using a phase locked loop.
[0015] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the first converter is a three level, three phase
converter, the first inverter is a two level, three phase inverter,
the second converter is a three level, three phase converter, the
second inverter is a two level, three phase inverter and the motor
is a six phase motor.
[0016] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include a
second drive system coupled to the source of AC power, the second
drive system to provide multi-phase drive signals to the motor, the
second drive system including: a further first drive having a
further first converter and a further first inverter, the further
first convertor including a further first positive DC bus and a
further first negative DC bus; a further second drive having a
further second converter and a further second inverter, the further
second convertor including a further second positive DC bus and a
further second negative DC bus; wherein the further first positive
DC bus and the further second DC positive bus are electrically
connected and the further first negative DC bus and the further
second negative DC bus are electrically connected; the motor to
receive the drive signals from the further first drive and the
further second drive.
[0017] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include a
first inductive interface coupled to the first inverter and the
second inverter, the first inductive interface including a
plurality of inductive elements, the first inductive interface
combining drive signals from the first inverter and the second
inverter for each phase of the drive signals; and a second
inductive interface coupled to the further first inverter and the
further second inverter, the second inductive interface including a
plurality of inductive elements, the second inductive interface
combining drive signals from the further first inverter and the
further second inverter for each phase of the drive signals;
wherein the motor receives drive signals from the first inductive
interface and the second inductive interface.
[0018] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the first inductive interface generates three phase drive
signals; the second inductive interface generates three phase drive
signals; and the motor has at least six phases.
[0019] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the motor is a 6 phase motor, the first drive system
providing three phase drive signals and the second drive system
providing an additional three phase drive signals.
[0020] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
wherein the number of drive systems comprises N drive systems, the
motor being a 3N phase motor.
[0021] In addition to one or more of the features described above
or below, or as an alternative, further embodiments could include
an elevator car; the machine to control motion of the elevator
car.
[0022] Other aspects, features, and techniques of embodiments will
become more apparent from the following description taken in
conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Referring now to the drawings wherein like elements are
numbered alike in the FIGURES:
[0024] FIG. 1 is a block diagram of components of an elevator
system in an exemplary embodiment;
[0025] FIG. 2 is a block diagram of a 2 level, 3 phase drive used
in an exemplary embodiment;
[0026] FIG. 3A is a block diagram of a 3 level, 3 phase drive used
in an exemplary embodiment;
[0027] FIG. 3B is a block diagram of a 3 level, 3 phase drive used
in an exemplary embodiment;
[0028] FIG. 3C is a block diagram of a 3 level, 3 phase drive used
in an exemplary embodiment;
[0029] FIG. 4 is a block diagram of a drive system including
paralleled drives in an exemplary embodiment;
[0030] FIG. 5 is a block diagram of a drive system including
paralleled drives in an exemplary embodiment;
[0031] FIG. 6 depicts synchronization of control signals between a
first drive and a second drive in an exemplary embodiment;
[0032] FIG. 7 is a block diagram of a drive system including
paralleled drives in an exemplary embodiment;
[0033] FIG. 8 is a block diagram of a drive system including
paralleled drive systems, each including parallel drives, in an
exemplary embodiment; and
[0034] FIG. 9 is a block diagram of a drive system including
paralleled converters in an exemplary embodiment.
DETAILED DESCRIPTION
[0035] FIG. 1 is a block diagram of components of an elevator
system 10 in an exemplary embodiment. Although embodiments are
described with respect to an elevator system, it is understood that
embodiments may be applied to other conveyance systems (e.g.,
trains, automobiles, marine). Elevator system 10 includes a source
of AC power 12, such as an electrical main line (e.g., 440 volt,
3-phase). The AC power 12 is provided to a regenerative drive
system 20. As described in further detail herein, drive system 20
includes a plurality of drives arranged in a parallel electrical
configuration. Each drive may include a converter to convert the AC
power 12 to a DC voltage. Each drive may include an inverter to
convert the DC voltage to multiphase, AC drive signals. Drive
signals from the drive system 20 are supplied to a multiphase
machine 22 to impart motion to elevator car 23. In an exemplary
embodiment, machine 22 includes a multiphase, permanent magnet
synchronous motor.
[0036] FIG. 2 is a block diagram of a 2 level, 3 phase drive 30
used in exemplary embodiments. Drive 30 includes a converter 32
having 3 phase legs, R, S and T. Each phase leg, R, S and T,
includes switches controlled by control signals from a drive
controller to convert AC power to DC power across a first DC bus 34
(e.g., positive) and a second DC bus 36 (e.g., negative). Drive 30
includes an inverter 40 having 3 phase legs, W, V, U. Each phase
leg, W, V, and U, includes switches controlled by control signals
from a drive controller to convert DC power across the DC bus 34,
36 to AC drive signals to power motor 21, which is part of machine
22.
[0037] FIG. 3A is a block diagram of a 3 level, 3 phase drive 50
used in an exemplary embodiment. Drive 50 includes a converter 52
having 3 phase legs, R, S and T. Each phase leg, R, S and T,
includes switches controlled by control signals from a drive
controller to convert AC power to DC power across a first DC bus 34
(e.g., positive) and a second DC bus 36 (e.g., negative). Converter
52 is a neutral point clamped (NPC) converter, in which the neutral
points in each phase leg R, S, and T are connected at a common,
converter neutral point 53. Drive 50 includes an inverter 54 having
3 phase legs, W, V, U. Each phase leg, W, V, and U, includes
switches controlled by control signals from a drive controller to
convert DC power across the DC bus 34, 36 to AC drive signals to
power motor 21, which is part of machine 22. Inverter 54 is a
neutral point clamped (NPC) inverter, in which the neutral points
in each phase leg W, V, and U are connected at a common, inverter
neutral point 55. An optional neutral point link 58 may be used to
electrically connect the converter neutral point 53 to the inverter
neutral point 55.
[0038] FIG. 3B is a block diagram of a 3 level, 3 phase drive 51
used in an exemplary embodiment. Drive 51 includes a converter 52
having 3 phase legs, R, S and T. Each phase leg, R, S and T,
includes switches controlled by control signals from a drive
controller to convert AC power to DC power across a first DC bus 34
(e.g., positive) and a second DC bus 36 (e.g., negative). Converter
52 is a T-type converter. Drive 51 includes an inverter 54 having 3
phase legs, W, V, U. Each phase leg, W, V, and U, includes switches
controlled by control signals from a drive controller to convert DC
power across the DC bus 34, 36 to AC drive signals to power motor
21, which is part of machine 22. Inverter 54 is a T-type inverter.
An optional neutral point link 58 may be used to electrically
connect a converter neutral point to an inverter neutral point.
[0039] FIG. 3C is a block diagram of a 3 level, 3 phase drive 53
used in an exemplary embodiment. Drive 53 includes a converter 52
having 3 phase legs, R, S and T. Each phase leg, R, S and T,
includes switches controlled by control signals from a drive
controller to convert AC power to DC power across a first DC bus 34
(e.g., positive) and a second DC bus 36 (e.g., negative). Converter
52 is an AT-type converter. Drive 53 includes an inverter 54 having
3 phase legs, W, V, U. Each phase leg, W, V, and U, includes
switches controlled by control signals from a drive controller to
convert DC power across the DC bus 34, 36 to AC drive signals to
power motor 21, which is part of machine 22. Inverter 53 is an
AT-type inverter. An optional neutral point link 58 may be used to
electrically connect a converter neutral point to an inverter
neutral point.
[0040] FIG. 4 is a block diagram of a drive system including
paralleled drives in an exemplary embodiment. As shown in FIG. 4,
two drives 30 and 30' are connected in parallel to provide drive
signals to motor 21. Each drive 30 and 30' is controlled by a
separate drive controller, 60 and 62, respectively. Drive
controllers 60 and 62 provide control signals to the drives 30 and
30', respectively, to control generation of the drive signals to
motor 21. Drive controllers 60, 62 may be implemented using a
general-purpose microprocessor executing a computer program stored
on a storage medium to perform the operations described herein.
Alternatively, drive controllers 60, 62 may be implemented in
hardware (e.g., ASIC, FPGA) or in a combination of
hardware/software.
[0041] Drives 30 and 30' are 2 level, 3 phase drives, such as that
shown in FIG. 2. Drives 30 and 30' are placed in parallel by
electrically connecting the positive DC bus 34 of drive 30 to the
positive DC bus 34 of drive 30' and electrically connecting the
negative DC bus 36 of drive 30 to the negative DC bus 36 of drive
30'. The 3 phase drive signals from drives 30 and 30' are connected
to an inductive interface 70, which combines each respective phase
from the drives 30 and 30' through inductive elements (e.g.,
inductors). For example, phase W from drive 30 and phase W from
drive 30' are connected to each other through separate inductive
elements in the inductive interface 70, and then applied to one
winding of 3-phase motor 21. Phases V and U are connected in a
similar manner. Inductive interface 70 allows for combining phases
from two separate drives 30 and 30'. Inductive interface 70 also
acts as a voltage suppression filter. Although two drives 30 and
30' are shown in FIG. 4, it is understood that embodiments may
include more than two drives connected in parallel.
[0042] FIG. 5 is a block diagram of a drive system including
paralleled drives in an exemplary embodiment. As shown in FIG. 5,
two drives 50 and 50' are connected in parallel to provide drive
signals to motor 21. Each drive 50 and 50' is controlled by a
separate drive controller, 60 and 62, respectively. Drive
controllers 60 and 62 provide control signals to the drives 50 and
50', respectively, to control generation of the drive signals to
motor 21.
[0043] Drives 50 and 50' are 3 level, 3 phase drives, such as that
shown in FIGS. 3A-3C. Drives 50 and 50' are placed in parallel by
electrically connecting the positive DC bus 34 of drive 50 to the
positive DC bus 34 of drive 50' and electrically connecting the
negative DC bus 36 of drive 50 to the negative DC bus 36 of drive
50'. Further, the inverter neutral point 55 of drive 50 is
connected to converter neutral point 53 of drive 50'.
Alternatively, the converter neutral point 53 of drive 50 is
connected to inverter neutral point 55 of drive 50'. In other
embodiments, the connection between the inverter neutral point 55
(converter neutral point 53) of drive 50 to the converter neutral
point 53 (inverter neutral point 55) of drive 50'may be eliminated,
and only the DC buses connected between drives 50 and 50'.
[0044] The 3 phase drive signals from drives 50 and 50' are
connected to an inductive interface 70, which combines each
respective phase from the drives 50 and 50' through inductive
elements. For example, phase W from drive 50 and phase W from drive
50' are connected to each other through separate inductive elements
in the inductive interface 70, and then applied to one winding of
3-phase motor 21. Phases V and U are connected in a similar manner.
Inductive interface 70 allows for combining phases from two
separate drives 50 and 50'. Although two drives 50 and 50' are
shown in FIG. 5, it is understood that embodiments may include more
than two drives connected in parallel.
[0045] To facilitate combining the drive signals of separate drives
(e.g., 30/30' or 50/50') at the inductive interface 70, it is
beneficial that the drive signals at the output of the drives be
synchronized. Due to variations in the drive controllers and
drives, using identical control signals may not result in
synchronized outputs from the drives. In order to aid in
synchronizing the outputs from two or more drives, drive
controllers 60 and 62 execute a process to align the control
signals provided to the respective drives. FIG. 6 depicts a first
control signal 80 from drive controller 60 for one phase of the
inverter 40 of drive 30, for example, and a second control signal
82 from drive controller 62 for one phase of the inverter 40 of
drive 30', for example. The control signals may be pulse width
modulation signals, commonly used in n-level drives. In operation,
a reference point 84 of the control signal is defined. As shown in
FIG. 6, the reference point 84 is a minimum value of the control
signal, however, any reference point may be used. During operation,
first drive controller 60 communicates to the second drive
controller 62 when the reference point has occurred in control
signal 80. Second drive controller 62 then determines when the
reference point occurs in control signal 82. If there is a
difference between when the reference point occurs in the first
control signal 80 and when the reference point occurs in the second
control signal 82, then one or both of the drive controllers 60 and
62 may adjust the period of the drive signal such that the
reference points occur at the same time. The first drive controller
60 or second drive controller 62 may use known techniques to adjust
the period of the drive signal, such as a phase locked loop
technique to reduce error between when the reference point occurs
in control signal 82 and when the reference point occurs in control
signal 84. This improves synchronization of the drive signals
between drives 30 and 30', which allows smaller inductive elements
to be used in inductive interface 70. The control signal
synchronization of FIG. 6 may be used with any number of drives,
and is not limited to two drives. The control signal
synchronization of FIG. 6 may be used with the drives other than
those shown in FIG. 4.
[0046] FIG. 7 is a block diagram of a drive system including
paralleled drives in an exemplary embodiment. Drive controllers 60
and 62 may be used in the embodiment of FIG. 7 to control drives 90
and 90'. FIG. 7 depicts the use of hybrid drives 90 and 90', where
the converter sections are 3 level, 3 phase converters 52 and the
inverter sections are 2 level, 3 phase inverters 40. FIG. 7 also
depicts an architecture that does not use an inductive interface
70. In FIG. 7, motor 21 is a 6 phase motor. Each phase of the 3
phase drive signals from drives 90 and 90' is connected to an
individual phase of motor 21. Motor 21 may have two (or four) sets
of galvanic electrically isolated windings sharing the same stator
and generating torque on a common rotor. This architecture can be
expanded by adding additional drives and using a motor with a
higher number of phases (e.g., 3 three-phase drives with a 9 phase
motor, 4 three-phase drives with a 12 phase motor).
[0047] FIG. 8 is a block diagram of an architecture including
paralleled drive systems, each including parallel drives, in an
exemplary embodiment. FIG. 8 depicts the use of multiple drive
systems 100 and 100', each including parallel drives 50 and 50'.
Drive controllers 60 and 62 may be used in the embodiment of FIG. 8
to control drives 50 and 50'. In the example of FIG. 8, two drive
systems 100 and 100' (each similar to that in FIG. 5) are used to
power a 6 phase motor 21. Each drive system 100 and 100' generates
a 3 phase drive signal output, where each phase is applied to a
winding of motor 21. Motor 21 may have sets of galvanic
electrically isolated windings sharing the same stator and
generating torque on a common rotor. It is understood that other
drive systems may be used in parallel, and embodiments are not
limited to the drive system of FIG. 5. Each drive system 100 and
100'may employ control signal synchronization as described with
reference to FIG. 6. This architecture can be expanded by adding
additional drive systems 100 and using a motor with a higher number
of phases (e.g., 3 drive systems with a 9 phase motor, 4 drive
systems with a 12 phase motor). In general terms, the system may
include N drive systems, with a motor being 3N phase motor.
[0048] FIG. 9 is a block diagram of a drive system including
paralleled converters and paralleled inverters in an exemplary
embodiment. AC power 12 is provided to separate reactors 120 and
120' and then to converters 122 and 122'. The output of converters
122 and 122' is supplied to a DC bus 124, which parallels the
positive and negative DC outputs from converters 122 and 122'. An
inverter 126 is made up of two parallel, 3 level IGBT inverters
controlled by a single controller and single gate drive. The
inverters use identical or nearly identical IGBTs, and thus may be
controlled by a single controller and gate drive signal, applied to
the IGBTs in parallel.
[0049] Embodiments include the use of paralleled drives in order to
meet high load demands without the need to design or source a
single, high power drive. Using parallel drives, and optionally
parallel drive systems, allows the drive system to meet load
demands through multiple, lower power drives. This eliminates the
cost and/or development time associated with a single, higher power
drive.
[0050] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting.
While the description has been presented for purposes of
illustration and description, it is not intended to be exhaustive
or limited to the form disclosed. Many modifications, variations,
alterations, substitutions, or equivalent arrangement not hereto
described will be apparent to those of ordinary skill in the art
without departing from the scope of the disclosure. Additionally,
while the various embodiments have been described, it is to be
understood that aspects may include only some of the described
embodiments. Accordingly, embodiments are not to be seen as being
limited by the foregoing description, but is only limited by the
scope of the appended claims.
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